Various embodiments of this invention facilitate the introduction of multiple fiber-optic thermometers into a measurement environment with a predetermined and fixed relative arrangement.
One application is for the medical profession. Certain types of prostrate cancer are treated by microwave radiation to heat and kill cancerous cells in the tumor. During this treatment, temperatures are measured at various locations within the tumor as the microwave radiation is applied in order to monitor and/or control the procedure. Fiber optic temperature sensors are used in this type of situation because they are compatible with the microwave fields employed, in contrast to a standard temperature sensor such as a thermistor or thermocouple. Accommodating multiple sensors with individual catheters for each sensor is cumbersome and time consuming, and may be difficult or impossible to insert into a relatively small volume including, but not limited to a prostrate. The number of required catheters, as well as the time and complexity for insertion into the relatively small volume to be monitored, need to be substantially reduced.
Another application involves the electric power industry. Monitoring for hot spots within electrical devices including, but not limited to, an electric power transformer and applying cooling or reduced operation, when needed, can extend lifetime of the electrical devices. Fiber-optic temperature sensors are compatible with the environment within such electrical devices that may include high-amplitude electric fields.
Past fiber-optic temperature sensors including, but not limited to, those sensors based upon fluorescence-decay technology employ a single temperature-sensing optical fiber equipped with a connector at one end. A temperature-sensitive phosphor is present on the other end (sensing tip). A furcation tube, beginning at the connector, may be incorporated to better protect most of the fiber. Typically, a section (tip extension) of the fiber adjacent to the sensing tip extends from the furcation tube with protection from environmental and impact damage accomplished by a thin-walled outer tube. The tip extension facilitates access to locations with relatively small size.
Previous fluorescence-decay fiber-optic sensor design with a single sensing tip has limitations when applied to applications requiring multiple points of measurements at a set of locations with a fixed relative spacing. This technique is time consuming and often impractical.